Two-dimensional woven fabrics for producing three-dimensional composite parts contain warp threads and/or weft threads made of a material that has tensile strength, such as, for instance carbon. In practice, difficulties frequently result if such two-dimensional woven fabrics are used for producing so-called “preforms”. This involves laying one or more woven fabric layers on top of one another and preforming them, to produce from them, in further processing steps, the composite part in its desired three-dimensional shape. The preform simplifies the later processing into the final component shape. The preform is intended already to have approximately the three-dimensional shape that the later, final composite part is also intended to have. Therefore, producing the preform requires that the two-dimensional woven fabric can be draped into the desired three-dimensional shape with as few problems as possible, and later reshaped into the finished composite part.
Despite the required drapability of the woven fabric, it must nevertheless be ensured that the desired strength is achieved. Therefore, the reinforcing threads must assume a specified position or direction in the three-dimensional composite part. As a rule, the materials that serve for producing such reinforcing yarns are expensive. Producing the preform involves cutting the two-dimensional woven fabrics to shape. The excess woven fabric material that does not correspond to the desired shape of the preform is removed. This gives rise to a large amount of labor and a large proportion of material waste.
JP 2014 181431 A discloses a two-dimensional woven fabric, wherein reinforcing yarns are glued to the warp threads and/or weft threads only in a certain area that is later to be cut out. The places that are glued are later cut out of the finished two-dimensional woven fabric. Even this process involves a large amount of clippings and manual effort.
DE 10 2008 036 347 A1 describes a process for introducing, during the machine weaving process, weft threads that additionally extend partially into the woven fabric width. This is intended to allow machine production, using Jacquard power looms, for example, of reconstructions of old broché fabrics. To form the woven fabric pattern, it is possible to insert weft threads that do not extend over the entire woven fabric width, but rather are only integrated into one section of the warp beam.
DE 10 2013 011 580 A1 describes a two-dimensional woven fabric with reinforcing weft threads, that are woven in a variable width with all or only a portion of the warp threads.